3 Chemicals You Actually Need to Open a Pool
Shock Use non-chlorine or chlorine shock to kill anything that grew in the water over winter.
Algaecide Add algaecide to prevent new algae from taking hold after you open the pool.
Stabilizer (cyanuric acid) Only add stabilizer if your cyanuric acid levels are low. It protects chlorine from sunlight. If your CYA is already good from last year, skip it.
Test and adjust pH and alkalinity first, but those are water balance basics, not opening chemicals. Ignore pool store opening kits with six bottles — most are overpriced filler.